Year	US Dollars adjusted for inflation)
1977	4429.54255
1978	4595.40356
1979	4952.92045
1980	5363.42303
1981	5596.68643
1982	5639.68578
1983	6009.30273
1984	6705.70255
1985	7315.81662
1986	8272.02436
1987	8945.48375
1988	9522.29418
1989	10087.26515
1990	10380.30783
1991	10509.99224
1992	10457.71409
1993	10772.02187
1994	11205.82219
1995	10440.70689
1996	10834.62877
1997	11117.09478
1998	11335.12856
1999	11470.9865
2000	11981.91636
2001	11191.10258
2002	11147.26358
2003	11683.46255
2004	12218.74486
2005	12857.1643
2006	14325.48102
2007	15466.9528
2008	15278.87405
2009	13270.6971
2010	12174.69786
2011	11789.79908
2012	12069.81138
2013	11928.21847
2014	12403.52822
2015	12771.76758
2016	13315.50863
2017	13618.3597